Colorectal cancers are classified as right/left-sided based on whether they occur before/after the splenic flexure, with established differences in molecular subtypes and outcomes. However, it is ...unclear if this division is optimal and whether precise tumor location provides further information.
In 1,876 patients with colorectal cancer, we compared mutation prevalence and overall survival (OS) according to side and location. Consensus molecular subtype (CMS) was compared in a separate cohort of 608 patients.
Mutation prevalence differed by side and location for
, and
Within left- and right-sided tumors, there remained substantial variations in mutation rates. For example, within right-sided tumors,
mutations decreased from 70% for cecal, to 43% for hepatic flexure location (
= 0.0001), while
V600 mutations increased from 10% to 22% between the same locations (
< 0.0001). Within left-sided tumors, the sigmoid and rectal region had more
mutations (
= 0.027), less
(
= 0.0009),
(
= 0.0033), or
mutations (
< 0.0001), and less MSI (
< 0.0001) than other left-sided locations. Despite this, a left/right division preceding the transverse colon maximized prognostic differences by side and transverse colon tumors had K-modes mutation clustering that appeared more left than right sided. CMS profiles showed a decline in CMS1 and CMS3 and rise in CMS2 prevalence moving distally.
Current right/left classifications may not fully recapitulate regional variations in tumor biology. Specifically, the sigmoid-rectal region appears unique and the transverse colon is distinct from other right-sided locations.
.
SMAD4 is an essential mediator in the transforming growth factor-β pathway. Sporadic mutations of SMAD4 are present in 2.1-20.0% of colorectal cancers (CRCs) but data are limited. In this study, we ...aimed to evaluate clinicopathologic characteristics, prognosis, and clinical outcome associated with this mutation in CRC cases. Data for patients with metastatic or unresectable CRC who underwent genotyping for SMAD4 mutation and received treatment at The University of Texas MD Anderson Cancer Center from 2000 to 2014 were reviewed. Their tumors were sequenced using a hotspot panel predicted to cover 80% of the reported SMAD4 mutations, and further targeted resequencing that included full-length SMAD4 was performed on mutated tumors using a HiSeq sequencing system. Using The Cancer Genome Atlas data on CRC, the characteristics of SMAD4 and transforming growth factor-β pathway mutations were evaluated according to different consensus molecular subtypes of CRC. Among 734 patients with CRC, 90 (12%) had SMAD4 mutations according to hotspot testing. SMAD4 mutation was associated with colon cancer more so than with rectal cancer (odds ratio 2.85; p<0.001), female sex (odds ratio 1.71; p = 0.02), and shorter overall survival than in wild-type SMAD4 cases (median, 29 months versus 56 months; hazard ratio 2.08; p<0.001 log-rank test). SMAD4 mutation was not associated with age, stage at presentation, colonic location, distant metastasis, or tumor grade. A subset of patients with metastatic CRC (n = 44) wild-type for KRAS, NRAS, and BRAF who received anti-epidermal growth factor receptor therapy with mutated SMAD4 (n = 13) had shorter progression-free survival duration than did patients wild-type for SMAD4 (n = 31) (median, 111 days versus 180 days; p = 0.003 log-rank test). Full-length sequencing confirmed that missense mutations at R361 and P356 in the MH2 domain were the most common SMAD4 alterations. In The Cancer Genome Atlas data, SMAD4 mutation frequently occurred with KRAS, NRAS, and BRAF mutations and was more common in patients with the consensus molecular subtype 3 of CRC than in those with the other 3 subtypes. This is one of the largest retrospective studies to date characterizing SMAD4 mutations in CRC patients and demonstrates the prognostic role and lack of response of CRC to anti-epidermal growth factor receptor therapy. Further studies are required to validate these findings and the role of SMAD4 mutation in CRC.
Transfer of next-generation sequencing technology to a Clinical Laboratory Improvement Amendments–certified laboratory requires vigorous validation. Herein, we validated a next-generation sequencing ...screen interrogating 740 mutational hotspots in 46 cancer-related genes using the Ion Torrent AmpliSeq cancer panel and Ion Torrent Personal Genome Machine (IT-PGM). Ten nanograms of FFPE DNA was used as template to amplify mutation hotspot regions of 46 genes in 70 solid tumor samples, including 22 archival specimens with known mutations and 48 specimens sequenced in parallel with alternate sequencing platforms. In the archival specimens, the IT-PGM detected expected nucleotide substitutions ( n = 29) and four of six insertions/deletions; in parallel, 66 variants were detected. These variants, except a single nucleotide substitution, were confirmed by alternate platforms. Repeated sequencing of progressively diluted DNA from two cancer cell lines with known mutations demonstrated reliable sensitivity at 10% variant frequency for single nucleotide variants with high intrarun and inter-run reproducibility. Manual library preparation yielded relatively superior sequencing performance compared with the automated Ion Torrent OneTouch system. Overall, the IT-PGM platform with the ability to multiplex and simultaneously sequence multiple patient samples using low amounts of FFPE DNA was specific and sensitive for single nucleotide variant mutation analysis and can be incorporated easily into the clinical laboratory for routine testing.
Consensus molecular subtyping (CMS) of colorectal cancer has potential to reshape the colorectal cancer landscape. We developed and validated an assay that is applicable on formalin-fixed, ...paraffin-embedded (FFPE) samples of colorectal cancer and implemented the assay in a Clinical Laboratory Improvement Amendments (CLIA)-certified laboratory.
We performed an
experiment to build an optimal CMS classifier using a training set of 1,329 samples from 12 studies and validation set of 1,329 samples from 14 studies. We constructed an assay on the basis of NanoString CodeSets for the top 472 genes, and performed analyses on paired flash-frozen (FF)/FFPE samples from 175 colorectal cancers to adapt the classifier to FFPE samples using a subset of genes found to be concordant between FF and FFPE, tested the classifier's reproducibility and repeatability, and validated in a CLIA-certified laboratory. We assessed prognostic significance of CMS in 345 patients pooled across three clinical trials.
The best classifier was weighted support vector machine with high accuracy across platforms and gene lists (>0.95), and the 472-gene model outperforming existing classifiers. We constructed subsets of 99 and 200 genes with high FF/FFPE concordance, and adapted FFPE-based classifier that had strong classification accuracy (>80%) relative to "gold standard" CMS. The classifier was reproducible to sample type and RNA quality, and demonstrated poor prognosis for CMS1-3 and good prognosis for CMS2 in metastatic colorectal cancer (
< 0.001).
We developed and validated a colorectal cancer CMS assay that is ready for use in clinical trials, to assess prognosis in standard-of-care settings and explore as predictor of therapy response.
Routine molecular testing in acute myeloid leukemia involves screening several genes of therapeutic and prognostic significance for mutations. A comprehensive analysis using single-gene assays ...requires large amounts of DNA, is cumbersome and timely consolidation of results for clinical reporting is challenging. High throughput, next-generation sequencing platforms widely used in research have not been tested vigorously for clinical application. Here we describe the clinical application of MiSeq, a next-generation sequencing platform to screen mutational hotspots in 54 cancer-related genes including genes relevant in acute myeloid leukemia (NRAS, KRAS, FLT3, NPM1, DNMT3A, IDH1/2, JAK2, KIT and EZH2). We sequenced 63 samples from patients with acute myeloid leukemia/myelodysplastic syndrome using MiSeq and compared the results with those obtained using another next-generation sequencing platform, Ion-Torrent Personal Genome Machine and other conventional testing platforms. MiSeq detected a total of 100 single nucleotide variants and 23 NPM1 insertions that were confirmed by Ion Torrent or conventional platforms, indicating complete concordance. FLT3-internal tandem duplications (n=10) were not detected; however, re-analysis of the MiSeq output by Pindel, an indel detection algorithm, did detect them. Dilution studies of cancer cell-line DNA showed that the quantitative accuracy of mutation detection was up to an allelic frequency of 1.5% with a high level of inter- and intra-run assay reproducibility, suggesting potential utility for monitoring response to therapy, clonal heterogeneity and evolution. Examples demonstrating the advantages of MiSeq over conventional platforms for disease monitoring are provided. Easy work-flow, high throughput multiplexing capability, 4-day turnaround time and simultaneous assessment of routinely tested and emerging markers make MiSeq highly applicable for clinical molecular testing in acute myeloid leukemia.
Next-generation sequencing (NGS) for molecular diagnostics allows simultaneous testing of activating oncogenes and tumor suppressor mutations in multiple signal pathways. Extended mutational ...profiling of advanced thyroid cancers may enhance considerations for targeted therapies. We analyzed clinically derived molecular profiling of 216 patients with advanced thyroid carcinoma using NGS (Ion Torrent Personal Genome Machine) from April 2012 to February 2014. We examined substitutions and small indels in 46 or 50 cancer-related genes using Ampliseq Cancer Hotspot panel in respect to tumor diagnosis and clinical correlations.Mutations were common in advanced thyroid carcinomas 154 (71%) predominately in targetable MAPK pathway (146/216, 68%), and several PI3K/AKT pathway (8, 4%; six as comutations).
mutation associated with papillary (94/139, 68%), poorly differentiated (4/39, 10%), and anaplastic (3/12, 25%) carcinomas.
mutations occurred in follicular (5/12, 42%) and poorly differentiated thyroid carcinoma (12/39, 31%). Tumor suppressor mutations (16, 7%) occurred predominantly in
in Hurthle cell (2/5, 40%, the only mutation), in anaplastic (3/12, 25%) and poorly differentiated thyroid carcinoma (4/39, 10%) some as comutations and in papillary thyroid carcinoma (5/139, 4%) always a comutation. Kaplan-Meier analysis of patients with poorly differentiated thyroid carcinoma containing activating mutations who received targeted therapeutics showed improved survival compared to similarly treated patients without mutations in targetable pathways (
= 0.02). In conclusion, MAPK pathway is the predominant target for therapy in advance thyroid carcinomas; adding NGS enables the identification of comutations associated with resistance (
). Within poorly differentiated thyroid carcinoma, the molecular profile may hold prognostic value in the era of targeted therapy.
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We report the experience with 2,000 consecutive patients with advanced cancer who underwent testing on a genomic testing protocol, including the frequency of actionable alterations across tumor ...types, subsequent enrollment onto clinical trials, and the challenges for trial enrollment.
Standardized hotspot mutation analysis was performed in 2,000 patients, using either an 11-gene (251 patients) or a 46- or 50-gene (1,749 patients) multiplex platform. Thirty-five genes were considered potentially actionable based on their potential to be targeted with approved or investigational therapies.
Seven hundred eighty-nine patients (39%) had at least one mutation in potentially actionable genes. Eighty-three patients (11%) with potentially actionable mutations went on genotype-matched trials targeting these alterations. Of 230 patients with PIK3CA/AKT1/PTEN/BRAF mutations that returned for therapy, 116 (50%) received a genotype-matched drug. Forty patients (17%) were treated on a genotype-selected trial requiring a mutation for eligibility, 16 (7%) were treated on a genotype-relevant trial targeting a genomic alteration without biomarker selection, and 40 (17%) received a genotype-relevant drug off trial. Challenges to trial accrual included patient preference of noninvestigational treatment or local treatment, poor performance status or other reasons for trial ineligibility, lack of trials/slots, and insurance denial.
Broad implementation of multiplex hotspot testing is feasible; however, only a small portion of patients with actionable alterations were actually enrolled onto genotype-matched trials. Increased awareness of therapeutic implications and access to novel therapeutics are needed to optimally leverage results from broad-based genomic testing.
Abstract
Background
The proportion of tumors of various histologies that may respond to drugs targeted to molecular alterations is unknown. NCI-MATCH, a collaboration between ECOG-ACRIN Cancer ...Research Group and the National Cancer Institute, was initiated to find efficacy signals by matching patients with refractory malignancies to treatment targeted to potential tumor molecular drivers regardless of cancer histology.
Methods
Trial development required assumptions about molecular target prevalence, accrual rates, treatment eligibility, and enrollment rates as well as consideration of logistical requirements. Central tumor profiling was performed with an investigational next-generation DNA–targeted sequencing assay of alterations in 143 genes, and protein expression of protein expression of phosphatase and tensin homolog, mutL homolog 1, mutS homolog 2, and RB transcriptional corepressor 1. Treatments were allocated with a validated computational platform (MATCHBOX). A preplanned interim analysis evaluated assumptions and feasibility in this novel trial.
Results
At interim analysis, accrual was robust, tumor biopsies were safe (<1% severe events), and profiling success was 87.3%. Actionable molecular alteration frequency met expectations, but assignment and enrollment lagged due to histology exclusions and mismatch of resources to demand. To address this lag, we revised estimates of mutation frequencies, increased screening sample size, added treatments, and improved assay throughput and efficiency (93.9% completion and 14-day turnaround).
Conclusions
The experiences in the design and implementation of the NCI-MATCH trial suggest that profiling from fresh tumor biopsies and assigning treatment can be performed efficiently in a large national network trial. The success of such trials necessitates a broad screening approach and many treatment options easily accessible to patients.
Therapeutically actionable molecular alterations are widely distributed across cancer types. The National Cancer Institute Molecular Analysis for Therapy Choice (NCI-MATCH) trial was designed to ...evaluate targeted therapy antitumor activity in underexplored cancer types. Tumor biopsy specimens were analyzed centrally with next-generation sequencing (NGS) in a master screening protocol. Patients with a tumor molecular alteration addressed by a targeted treatment lacking established efficacy in that tumor type were assigned to 1 of 30 treatments in parallel, single-arm, phase II subprotocols.
Tumor biopsy specimens from 5,954 patients with refractory malignancies at 1,117 accrual sites were analyzed centrally with NGS and selected immunohistochemistry in a master screening protocol. The treatment-assignment rate to treatment arms was assessed. Molecular alterations in seven tumors profiled in both NCI-MATCH trial and The Cancer Genome Atlas (TCGA) of primary tumors were compared.
Molecular profiling was successful in 93.0% of specimens. An actionable alteration was found in 37.6%. After applying clinical and molecular exclusion criteria, 17.8% were assigned (26.4% could have been assigned if all subprotocols were available simultaneously). Eleven subprotocols reached their accrual goal as of this report. Actionability rates differed among histologies (eg, > 35% for urothelial cancers and < 6% for pancreatic and small-cell lung cancer). Multiple actionable or resistance-conferring tumor mutations were seen in 11.9% and 71.3% of specimens, respectively. Known resistance mutations to targeted therapies were numerically more frequent in NCI-MATCH than TCGA tumors, but not markedly so.
We demonstrated feasibility of screening large numbers of patients at numerous accruing sites in a complex trial to test investigational therapies for moderately frequent molecular targets. Co-occurring resistance mutations were common and endorse investigation of combination targeted-therapy regimens.
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